Di"a*phragm (?), n. [L. diaphragma, Gr. , fr. to fence by a partition wall; through + , , to fence, inclose; prob. akin to L. fareire to stuff: cf. F. diaphragme. See [Farce].]

1.

A dividing membrane or thin partition, commonly with an opening through it.

2. [Anatomy|Anat.]

The muscular and tendinous partition separating the cavity of the chest from that of the abdomen; the midriff.

3. [Zoology|Zool.]

A calcareous plate which divides the cavity of certain shells into two parts.

4. Opt.

A plate with an opening, which is generally circular, used in instruments to cut off marginal portions of a beam of light, as at the focus of a telescope.

5. Mach.

A partition in any compartment, for various purposes.

[Diaphragm pump], one in which a flexible diaphragm takes the place of a piston.

© [Webster 1913].

diaphragm (definition)